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Properties of Minerals

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minerals- A mineral is a natural,inorganic substance with a crystal structure and chemical composition
inorganic- not formed from living things
crystal- A solids atoms that are packed in a pattern which repeats endlessly
element- A material that is made up of a certain type of atom
compound-two or more elements combined containing similar properties
Mohs Hardness Scale- A scale that scores ten minerals from softest to hardest
streak-reveals the color of mineral's powder
luster-shows how different minerals reflect light from their surfaces
cleavage- A certain characteristic that describes how brittle and weak a mineral is
fracture-revealed when a mineral breaks in a strange
fluorescence-minerals growing under ultra-violet light

Outline

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What is a Mineral

• more than 3000 minerals
• Naturally Occurring
  • all minerals are naturally occurring
• Inorganic
  • minerals must not be made from a living substance
• Solid
  • minerals are solid
    • containing a specific volume and shape
      • solid keeps in shape since minerals can't flow
• Crystal Structure
  • sometimes crystal structures are visible
  • others can only be seen under a microscope
• Definite Chemical Composition
  • certain set of atoms to create a mineral
    • almost all minerals are compounds
      • each compound has its own properties

Identifying Minerals

• each mineral has its own properties to identify itself
• hardness
  • one of the best clues used for identifying minerals
  • Mohs Hardness scale
    • used to rank minerals on how hard they are
      • the softest is Talc,the hardest is diamond
• Color
  • only a few minerals have its own color
    • other minerals can always come in several different colors,like quartz
• streak
  • the color of the minerals powder when it is rubbed or scratched against a hard surface
  • the color of the mineral and its powder are often different
• Luster
  • describes how a mineral shines light off of its surface
    • galena is an ore of lead with bright metallic luster
    • Malachite contains copper and has a silky luster
• Density
  • each mineral has a its own density
  • geologists use balances to figure out the exact weight of each mineral
    • minerals are also placed in water to notice how much water it displaces
      • the volume water equals the volume of the sample
        • dividing sample's mass by its volume is the total density of the mineral
• Crystal Systems
  • they are classified into six groups called crystal systems
    • sometimes a crystal structure has the same crystal structure of its mineral
• Cleavage and Fracture
  • cleavage is a clue to help identify minerals
    • when a mineral splits easily it has the property of cleavage
      • it depends on the pattern of atoms in its crystals
  • a fracture shows how a mineral looks like when it breaks in a strange way
• Special Properties
  • minerals can also be identified by several special properties
    • flourescence is an example of a special property
      • minerals that glow under ultra violet light have flourescence

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